Question about JBL PB12 Subwoofer

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JBL PB12 standby WAY too sensative

I listen to classical music that tends to have a very wide dynamic range. At lower volume levels this amp turns off, or even worse, flickers on/off very rapidly. Just turning the music up is not possable unless I want my house to rumble to the DJ's voice after the piece is over. Is there a way to disable this standby? Or better yet, is there a way to lower the threshold or extend the time before it goes to standby? Like 5-10 minutes after threshold is met, unless it is again exceeded. Like a how a screensaver works on a PC. Great sounding system, have had it for about 6 years. Thanks for any solutions. And a shaking of the fist for any bad news. :P

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Re: JBL PB12 standby WAY too sensative

Capacitor C42 is bad. You should have a 15 minute pause before going back into mute mode. If the cap. is really bad it will distort the sound and cause cutoff.

David S.

Posted on Feb 12, 2009

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Re: JBL PB12 standby WAY too sensative

It sounds like there are failing parts in the amp and possibly in the power supply sections. You should contact JBL to find out their service rep in your area.

This unit will not be cheap to service. But, you can start by investigating to know where you are going with it.

Jerry G.

Posted on Apr 28, 2008

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Hello there..Thats normal only if your sub volume and the pre amp is turned up..Your amp is the cause of the speaker jump..Turn amp volume sub level down a few and check your wire from sub to amp..If all of that is good is a normal operation for pre amp warm up in sub if level is turn to max..Try unplugging amp freom sub then turn sub on stand alone(just sub outlet plugged in and no wires from base amp plugged in..If sub stops the its the amp making the problem..If it still is there then the pre amp is either dusty on inside or the outlet plug that it is plugged in doesnt have a good ground..Hope these help to solve your problem..Have a great day...

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